Justification:Hypselobarbus thomassi is reported from several drainages north and south of Palghat Gap in the Western Ghats. However, only two areas (one each in Netravathi and Kabini rivers), both part of the Cauvery catchment in Karnataka and Kerala north of the Palghat Gap, are confirmed reports while the southern Western Ghats populations are considered a different taxon. Based only on the confirmed identities in Karnataka and northern Kerala, the species is restricted to less than 10 km² area, but in two severely fragmented locations. Recent surveys in the two areas have only reported one specimen from Netravathy indicating declines in the populations due to several threats in the areas. Although this species could be assigned a Data Deficient category due to taxonomic confusion, the assessment based on confirmed taxonomy indicates that it is Critically Endangered. Recommendations for urgent surveys and population monitoring in the known areas as well as taxonomic validation of the other populations are made.

Endemic to the Western Ghats (Dahanukar et al. 2004). There seems to be a uncertainty regarding the exact distribution of this species. Apart from Nethravati River (which is around the type locality) (Menon 2004), H. thomassi has been recorded from Periyar (Thomas 2004), Kabini (Shaji and Easa 2003) and Kallada rivers (Kurup et al. 2004) in Kerala. Recent studies have indicated that only three species of Hypselobarbus viz. H. curmuca, H. kolus and H. kurali is present in River Kallada (Abraham et al. 2010), and that the reports of H. thomassi from this river are not correct and are cases of misidentifications (Robin Abraham pers. comm). Given the taxonomic ambiguities existing within the Genus Hypselobarbus, the records of this species from Periyar (Thomas 2004) and Kallada (Kurup et al. 2004) needs to be validated and are excluded from this assessment.

There is no information on the population status of H. thomassi, nor are they any recent records from anywhere in Kerala or Karnataka. It is also known that an extensive search in South Canara turned up only one specimen (Menon 2004).

There is a need for concerted studies to determine the exact distribution ranges of this species and clear the existing taxonomic ambiguities within the genus Hypselobarbus. As there are no recent records of this species, it is to determined whether these are attributed to large scale population declines throughout its range or taxonomic issues. The Nethravati and Kabini rivers of Karnataka and Kerala, where the species might be existing, needs to be surveyed extensively.

In-Place Research, Monitoring and Planning Action Recovery plan:No Systematic monitoring scheme:NoIn-Place Land/Water Protection and Management Conservation sites identified:Yes, over part of range Occur in at least one PA:No Area based regional management plan:No Invasive species control or prevention:NoIn-Place Species Management Harvest management plan:No Successfully reintroduced or introduced beningly:No Subject to ex-situ conservation:NoIn-Place Education Subject to recent education and awareness programmes:No Included in international legislation:No Subject to any international management/trade controls:No

Kurup, B.M., Radhakrishnan, K.V. and Manojkumar, T.G. 2004. Biodiversity Status of Fishes Inhabiting Rivers of Kerala (South India) With Special Reference to Endemism, Threats and Conservation Measures. In: R.L. Welcomme and T. Petr (eds), Proceedings of the second international symposium on the management of large rivers for fisheries 2: 316. Cambodia.

Menon, A.G.K. 1999. Check list - fresh water fishes of India..

Menon, A.G.K. 2004. Threatened Fishes of India and their Conservation.